The present invention relates in general to smoke processing and more particularly concerns novel apparatus and techniques for removing essentially all nitrosamines and secondary amines from tobacco smoke.
In TOBACCO for June 19, 1970, in an article entitled "The Smoking and Health Issue: Research Study Efforts Need to be Re-Oriented," it states on page 28:
The presence or absence of the potent carcinogens nitrosamines in tobacco smoke is currently a controversial question. It has been assumed that secondary amines and oxides of nitrogen, present in tobacco smoke, could react and produce nitrosamines which might explain the tumorigenic activity of tobacco smoke in animals. PA1 These compounds were found in the smoke of cigarettes containing high levels of nitrates and volatile bases but not in the smoke from cigarettes with normal amounts of these leaf constituents. Further work indicated that all of the isolated nitrosamines may be artifacts formed in the smoke collection train and may not actually exist in the mainstream smoke. The nitric oxide present in cigarette smoke may be oxidized progressively to nitrogen dioxide in the traps and the combinations of oxides may react with amines to form the said nitrosamines. Consequently, no valid conclusion can be reached regarding the presence of nitrosamines in smoke immediately leaving the but end of a cigarette. PA1 Tobacco contains several secondary amines, particularly pyrrolidine to the extent of 0.01 percent. These amines could be released and ingested when tobacco is chewed, particularly when mixed with lime. Cigarette smoke contains many secondary amines, including pyrrolidine and piperidine. These amines could dissolve in the saliva during smoking and be converted to nitrosamines in the stomach. Such nitrosamines could be absorbed and give rise to tumours of the lung systemically, a property of several nitrosamines. Infra p. 53. (footnotes omitted) PA1 Unfortunately, it has been found that such prior art filters do not in fact remove or even sufficiently reduce the carcinogens present in tobacco smoke, that is, the components known to induce cancer and other disorders in rats. PA1 It has long been desired, therefore, and the object of many research projects of considerable cost to provide a tobacco smoke filter which is particularly effective against the carcinogens present in tobacco smoke while not eliminating therefrom the essential taste sought by tobacco smokers. PA1 There are such a large number of organic powders well-known in the art as being capable of compression to tablet form that it is superflous to mention any one in particular. PA1 Among the inorganic powders capable of being compressed in such a manner are: --common inorganic salts such as sodium carbonate, sodium bicarbonate, calcium carbonate, sodium sulphate etc; oxides such as alumina, magnesia; siliceous materials such as Kieselguhr, diatomaceous earth, celite, silicic acid; ion exchangers such as Dowex 50, Zeo-Karb 226, Bio-rad Z P-1- Bio-rad Z T-1, Bio-rad Z M-1, Bio-rad AHP-1, selectacel; zeolites and molecular sieves, 4A, 5A, 13X; amorphous powders such as different types of vegetable and bone charcoal. PA1 In addition to the above a number of organic materials are available which can be readily pressed in the form of a tablet, some of which are the following: Ethyl Cellulose, polyethylene glycol of various molecular weights, polyvinyl pyrrolidone, sucrose fatty acid ester, cellulose acetate, potato and rice starch, crystalline and paper cellulose. (p. 5) PA1 There can also be used granular absorbents such as silica gel and ion exchange resins, e.g. cation exchange resins such as sulfonated styrene-divinyl benzene copolymer (available commercially as Dowex 50), sulfonated phenolformaldehyde and ethylene glycol dimethacrylate-methacrylic acid copolymer and anion exchange resins such as phenol-tetraethylene pentamine-formaldehyde resin and quaternary ammonium resins prepared by reacting a tertiary amine with a haloalkylated cross-linked copolymer of a monovinyl hydrocarbon and a polyvinyl hydrocarbon, e.g. the reaction product of trimethyl amine with a chloromethylated cross-linked copolymer of 92% styrene and 8% divinyl benzene by weight (Amberlite IRA-400) (Column 2, lines 28-46).
In NATURE for Jan. 3, 1970, applicants stated in an article entitled "Nitrosamines as Environmental Carcinogens" at page 23:
With the aid of applicant Dr. Lijinsky nitrosamines in cigarette smoke condensate was positively identified and reported upon in a letter in NATURE for Apr. 7, 1972, pp. 307-08.
U.S. Pat. No. 3,903,898 granted Sept. 9, 1975, on an application filed May 21, 1974, is concerned with removing carcinogens found in tobacco smoke, but fails to mention secondary amines or nitrosamines or that essentially all of these substances should be removed from tobacco smoke. As recognized in that patent the concern of smokers with the possible presence in tobacco smoke of cancer-inducing components led to the development of various filtering materials for use in or with cigarettes, cigars and pipes, primarily designed to remove nicotine and the tarry components of cigarette smoke from the latter prior to its induction into the buccal cavity incorporated in cigarettes as so-called "filter tips", for replaceable use in cigarette and cigar holders and in the stems of pipes. The patentee there states in column 1 beginning at line 24:
Among the prior art is Australian Pat. No. 287594 published Nov. 10, 1966, on an invention of Tynan et al. That patent discloses an annular flavour ring located between the cigarette body 10 and filter 11, the flavour ring being used in conjunction with Millipore and/or normal cellulose acetate filters. The flavour ring has one or more apertures for the passage of smoke, the size and arrangement being such as to accelerate smoke passing through and thereby causing the deosition from the smoke of tars, nicotine and particular matter, the material of the ring holding an essence or other flavouring substance which is given up to the smoke as the cigarette is smoked, the word ring meaning any form of disc, plate, tablet or the like having in it one or more apertures. This flavour ring is made like medicinal tablets, and the patent states:
This patent does not discuss the carcinogenic effects of nitrosamines or secondary amines or removing essentially all nitrosamines and secondary amines from the tobacco smoke. Dowex 50 is a sulfonated styrene divinyl benzene colpolymer that is ineffective in removing nitrosamines from tobacco smoke. While the patent mentions silicic acid as an inorganic powder capable of being compressed into an annular tablet to form the annular flavour ring, the patent does not discuss using enough silicic acid to remove essentially all secondary amines from the tobacco smoke passing through the flavour ring, and the structure of the flavour ring is such that it could not remove essentially all secondary amines and nitrosamines because smoke passing through the opening in the flavour ring without contacting the surrounding chemicals will retain nitrosamines and secondary amines.
Another example of a prior art cigarette filter for removing tars and nicotine with high efficiency is disclosed in Noznick U.S. Pat. No. 3,313,305. That patent states:
Sadtler U.S. Pat. No. 2,007,407 discloses, "I have found that when such substances as colloidal silicic acid (known in the trade as `silica gel`) . . . are added to the tobacco in the course of manufacturing operations, that cigarettes made therefrom produce a much more agreeable smoke than when such substances, or any one or more of them, are absent (column 1, lines 45-column 2, line 2)." The silica gel there disclosed, because it is a dehydrating agent, commonly used industrially for this purpose, has the effect of tending to dry the smoke and is a substantially dehydrated colloidal silica that is neutral without affinity for basic amines.
Schreus U.S. Pat. No. 2,815,760 discloses a tobacco smoke filter and recommends using "secondary amines derived from polystyrene, such as for instance Amberlite IRA-400 . . . (column 2, lines 23-34)." This patent teaches that "no easily volatile amines or bases should be used because they would leave the filter during the smoking process, thus unfavorably affecting the aroma (column 3, 11. 64-66)." The patent does not mention carcinogens, nor that essentially all secondary amines and nitrosamines should be removed from the tobacco smoke.
It is an important object of this invention to provide a means and method for removing carcinogens from tobacco smoke.
It is a further object of this invention to provide a means and method for removing essentially all nitrosamines and secondary amines from tobacco smoke.
It is another object of the invention to achieve one or more of the preceding objects while also removing higher order amines from the tobacco smoke.
It is a further object of the invention to achieve one or more of the preceding objects with methods and means that are relatively inexpensive and may be used with relatively high efficiency.